JPH0240459A - Crystal precipitation prevention of absorbing liquid in absorption refrigerator - Google Patents

Abstract

PURPOSE:To prevent the precipitation of the crystal of absorbing liquid by introducing a heat medium in the absorbing liquid to dilute when the difference between the crystal precipitation temperature at the concentration of thick absorbing liquid and the temperature of the thick absorbing liquid at the outlet of a recuperator is lower than the fixed temperature. CONSTITUTION:The temperature Tc of condensed water is detected by a condensed water temperature detector 22, the temperature Tr of thick absorbing liquid at the outlet of a regenerator by a first absorbing liquid temperature detector 23 to input in a computing element 25 respectively and the concentration of the thick absorbing liquid is calculated from the boiling point of the absorbing liquid in a pressurizing state of a condenser 6 and the regenerator at the temperature Tc of the condensed water. The crystal precipitation temperature at the absorbing liquid concentration is compared with the thick absorbing liquid temperature Tr at the outlet of the recuperator 18 detected by a second absorbing liquid temperature detector 24 to input. When the temperature difference is equal to or lower than the fixed value, an opening signal is transmitted from the computing element 25 to open an automatic closing valve 19, the condensed water of a condensed water circulating pipe 11 is introduced in a diluted absorbing transfer pipe 8 and the absorbing liquid is diluted to prevent the crystal precipitation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for preventing crystal precipitation of an absorption liquid in an absorption refrigerator.

BACKGROUND OF THE INVENTION In recent years, for example, there have been air conditioners for whole meat that use absorption refrigerators, and in these absorption refrigerators, an absorption liquid (for example, an aqueous lithium bromide solution) is used. This absorption liquid is used in a highly concentrated state, and if the concentration becomes too high, crystals are likely to precipitate. Crystals will deposit in the concentrated absorption liquid transfer pipe, obstructing the flow of the absorption liquid, and causing the refrigerator to performance. Therefore, −I21! A sample of a highly concentrated absorbent liquid was sampled to check its concentration, and if the concentration was too high, the absorbent liquid was diluted by supplying water, which is an example of a heat medium, into the absorbent liquid.

Problems to be Solved by the Invention However, crystal precipitation in the absorption liquid is greatly influenced by temperature as well as concentration. Refrigeration capacity may decrease due to dilution.

The present invention solves the above problems and prevents the crystal precipitation of the absorption liquid in an absorption refrigerator by accurately diluting the absorption liquid and preventing crystal precipitation of the absorption liquid without reducing the capacity of the refrigerator. The purpose is to provide a method.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides an evaporator for evaporating a heat medium, an absorber for absorbing heat tlX vapor generated in the evaporator into an absorption liquid, and a heat a! A regenerator that absorbs steam and heats the diluted absorption liquid, and the heat obtained from this regenerator! I! a condenser for condensing vapor; a dilute absorption liquid transfer pipe for transferring the dilute absorption liquid in the absorber to the regenerator via a heat recovery device; In order to prevent crystal precipitation of the absorption liquid in an absorption refrigerator equipped with an absorption liquid transfer pipe (a) that transfers the absorption liquid to the absorber via the The temperature of the concentrated absorption liquid at the regenerator port of the concentrated absorption liquid transfer pipe and the temperature of the concentrated absorption liquid at the heat recovery device outlet are detected, and the heat medium temperature in the condenser and the temperature of the concentrated absorption liquid at the regenerator port are detected. temperature to fa
The temperature of the absorbing liquid is equalized, and when the difference between the crystal precipitation temperature at the concentration of the concentrated absorbing liquid and the temperature of the concentrated absorbing liquid at the outlet of the heat recovery device becomes equal to or less than a predetermined temperature, the heat medium is transferred to the absorbing liquid. It is designed to dilute the absorption liquid by introducing it into the liquid.

Effect In the above method, the temperature at the exit of the heat recovery device of the concentrated absorption liquid, where crystals tend to precipitate because it has the highest concentration and the lowest temperature, is
The absorption liquid is diluted when the crystal precipitation temperature of the concentrated absorption liquid reaches a predetermined temperature range, so even if the humidity of the absorption liquid changes with the temperature fluctuation of the heating medium, the absorption liquid can be accurately extracted. It can be diluted and does not cause a decrease in the capacity of the refrigerator or crystallization of the absorption liquid due to overdilution of the absorption liquid.

EXAMPLE An example of the present invention will be described below with reference to FIGS. 1 and 2.

In the schematic diagram of an absorption refrigerating machine shown in Fig. 1, the absorption refrigerating machine includes an evaporator 1 that evaporates water, which is an example of a heat medium, and an evaporator 1 that evaporates water vapor generated in the evaporator 1. An absorber 3 having a lithium bromide (Liar) aqueous solution (hereinafter referred to as absorption liquid) that is guided through a communication part 2 and absorbs this water vapor, and a diluted absorption liquid whose concentration has been reduced by absorbing water vapor is heated. A regenerator 4, a condenser 6 that guides water vapor generated by heating in the regenerator 4 through a communication part 5 and condenses the water vapor, and a W
f A dilute absorption liquid transfer pipe 8 having a liquid liquid pump pipe to transfer the dilute absorption liquid in the absorber 3 to the regenerator 4, and a condensing liquid pump pipe to transfer the condensed water condensed in the condenser 6 to the evaporator 1. The condensed water transfer pipe 9 has a water transfer pipe 9 and a heat medium pump 10 in the middle, and transfers condensed water, which is a heat medium accumulated at the bottom of the condenser 6, to the condensed water transfer pipe 9.
II condensed ice water circulation pipe 11 that circulates into the condenser 36 through a part of the water vapor, and a concentrated absorption liquid transfer pipe that transfers the concentrated absorption liquid that has become concentrated after water vapor is separated in the regenerator 4 to the absorber 3. 12
a first heat exchanger 13 disposed in the evaporator 1 for cooling a fluid to be cooled, such as water fA'1j; and a second heat exchanger 13 disposed in the absorber 3 for internal cooling fJJ. 14, a cooled ffl/'IJ fluid pipe 15 for guiding water, which is a fluid to be cooled, to the first heat exchanger 13, and a second heat exchanger 1.
A cooling fluid pipe 16 for guiding cooling water, which is a cold fJJ fluid, to 4 (the outlet side portion of this cooling fluid pipe is led into the condenser G to remove condensation heat); A heating pipe 17 for heating the absorbent disposed in the regenerator 4 is provided between the concentrated absorbent liquid transfer pipe 12 and the dilute absorbent liquid transfer pipe 8 to transfer the heat of the concentrated absorbent to the dilute absorbent side. It is equipped with a heat recovery device 18 for recovering heat.

A condensed water introduction pipe 20 with an automatic opening/closing valve 19 interposed between the heat medium pump 10@drawing side of the visiting condensed water circulation pipe 11 and the solution pump 7 suction side of the diluted absorption liquid transfer pipe 8 is provided. The condensed water introduction pipe 20 and the automatic opening/closing valve 19 constitute a crystal prevention device 21. The condenser 6 is equipped with a condensed water temperature detector 22 that detects the condensed water temperature (condensed temperature>TC).
will be placed. Further, a first absorption liquid temperature detector 23 is arranged near the outlet of the regenerator 4 of the concentrated absorption liquid transfer pipe 12, and a second absorption liquid temperature detector 24 is arranged near the exit of the heat recovery device 18. The first absorption liquid temperature detector 23 detects the temperature Tr of the concentrated absorption liquid at the start of the regenerator 4, and the second absorption liquid temperature detection 824 detects the temperature Tr of the concentrated absorption liquid at the most concentrated temperature (II temperature). Temperature T of the concentrated absorption liquid at the outlet of the heat exchanger 18
Detect h. These temperature detectors 22, 23, and 24 are, for example, thermometers, and the detected values are input to the calculator 25.

This calculator 25 has data showing the concentration and boiling point rise of the lithium bromide aqueous solution as shown in FIG. data is input, and the crystal precipitation temperature Tk,
When the temperature difference t between the temperature Th of the concentrated absorption liquid at the outlet of the heat recovery device 18 becomes a predetermined temperature or less, for example, 5° C. or less, the automatic opening/closing valve 19 is activated. The device is configured to output an opening operation signal to the device.

Table 1 In the above configuration, during normal operation, the action of evaporation → absorption → regeneration → condensation is repeated, and the cooling capacity is exhibited. For example, water, which is a fluid to be cooled, that is circulated through the indoor heat exchangers of eight air conditioners is cooled u1 in the first heat exchanger 13 provided in the evaporator 1. For example, as shown in Figure 2,
Condensed water temperature Th=50℃ by condensed water temperature detector 22
is detected and input to the calculator 25, and the temperature Tr=t07°C of the concentrated absorption liquid at the outlet of the regenerator 4 is detected by the first absorbent liquid temperature detector 23 and input to the calculator 25, The pressure of the condenser 6 and the regenerator 4 is 95n+1)-.
11 degrees Xr of the concentrated absorption liquid from the boiling point of the absorption liquid in the IQ state
= 64%, and the crystal precipitation temperature Tk = 35° C. at this absorption liquid concentration The temperature Th of the concentrated absorption liquid is compared with 58°C.

Then, when the temperature difference t becomes a predetermined temperature, for example, 5° C. or less, an opening signal is sent from the sieve 25 to the automatic opening/closing valve 19 operation 111J device of the crystal prevention device 21, and the automatic opening/closing valve 19 is opened. Then, the condensed water in the condensed water circulation pipe 11 is introduced into the diluted absorption liquid transfer pipe 8 to dilute the absorption liquid to lower its concentration and prevent crystal precipitation of the absorption liquid.

The automatic zero closing valve 19 is closed by issuing a closing operation signal from the computing unit 25 when the temperature difference therebetween reaches a predetermined temperature exceeding 5°C.

In the case shown in the Dueling chart in Figure 2, the temperature difference t is greater than 5°C, and there is no risk of crystal precipitation of the absorbent. However, if the condensed water temperature is low, The temperature Th at the outlet 18 has also become lower and the temperature difference is 5℃.
The crystallization prevention device 21 is activated by a command from the computing unit 25, and the condensed water in the evaporator 1 is introduced into the dilute absorption liquid transfer pipe 8. Note that this introduction
The water level of the condensed water in the diluted absorption liquid transfer pipe 8 is set higher than that of the diluted absorbent liquid transfer pipe 8, thereby making use of the positional head pressure and the suction force of the solution pump 7.

By the way, in the drawing, the steamer 1, absorber 3, regenerator 4, and condenser 6 are shown integrally, but of course this is a schematic diagram, so in reality, each device may be different depending on the situation. It has a separate configuration.

Effects of the Invention As described above, according to the present invention, the concentration of the absorption liquid is calculated from the heat medium temperature of the condenser and the temperature of the concentrated absorption liquid at the outlet of the regenerator, and the crystal precipitation temperature of the absorption liquid at this concentration is calculated. The temperature of the concentrated absorption liquid at the outlet of the heat recovery unit is compared with the temperature of the concentrated absorption liquid at the outlet of the heat recovery device, which is at a low temperature and high concentration where crystals are most likely to precipitate, and when the temperature reaches a predetermined temperature range, the absorption liquid is diluted with the heating medium, which reduces the fluctuation in the temperature of the heating medium. Even if the temperature of the absorption liquid may fluctuate due to the temperature of the absorption liquid, it can accurately respond to the temperature of the absorption liquid without reducing the capacity of the refrigerator due to over dilution of the absorption liquid or causing crystal precipitation of the absorption liquid due to a drop in temperature. The absorption liquid can be diluted and its concentration can be reduced to prevent crystal precipitation of the absorption liquid.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a schematic diagram showing the general structure of an absorption refrigerator, and FIG. 2 is a Düringert diagram showing the concentration and boiling point rise of an aqueous lithium bromide solution, which is an absorption liquid. It is. 1... Evaporator, 3... Absorber, 4... Regenerator, 6
Condenser, 8 Dilute absorption liquid transfer pipe, 12 Concentrated absorption liquid transfer pipe, 18 Heat recovery device, 19 Automatic opening/closing valve, 20 Condensed water introduction pipe , 21... Crystallization prevention device, 22... Condensed water temperature detector, 23... First absorption liquid temperature detector, 24... Second absorption liquid temperature detector,
25...Enkyoki, TC...Condensed water temperature, 1'r・
...Concentrated absorption liquid regenerator outlet temperature, 1-h...Concentrated absorption liquid heat recovery device outlet temperature, X'...Absorption liquid concentration, Tk...
・Crystal precipitation temperature.

Claims (1)

[Claims] 1. An evaporator that evaporates the heat medium, an absorber that absorbs the heat medium vapor generated in the evaporator into an absorption liquid, and a regenerator that absorbs the heat medium vapor and heats the diluted absorption liquid. a condenser for condensing the heat medium vapor obtained in the regenerator; a dilute absorption liquid transfer pipe for transferring the dilute absorption liquid in the absorber to the regenerator via a heat recovery device; When preventing crystal precipitation of the absorption liquid in an absorption refrigerator equipped with a concentrated absorption liquid transfer pipe that transfers the regenerated concentrated absorption liquid to the absorber via the heat recovery device, the heat in the condenser is prevented. In addition to detecting the temperature of the medium, the temperature of the concentrated absorption liquid at the outlet of the regenerator of the concentrated absorption liquid transfer pipe and the temperature of the concentrated absorption liquid at the outlet of the heat recovery device are detected, and the temperature of the concentrated absorption liquid in the condenser is determined. The concentration of the concentrated absorption liquid is calculated from the temperature of the concentrated absorption liquid at the outlet of the regenerator, and the difference between the crystal precipitation temperature at the concentration of the concentrated absorption liquid and the temperature of the concentrated absorption liquid at the outlet of the heat recovery device is equal to or lower than a predetermined temperature. 1. A method for preventing crystal precipitation of an absorption liquid in an absorption refrigerator, which comprises diluting the absorption liquid by introducing a heating medium into the absorption liquid when the absorption liquid is absorbed.